Substrate Drying via Sublimation Agent Film and Vaporization Cooling
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Solution Overview
Problem
The existing substrate drying methods face challenges in forming a solid sublimation-agent film without contamination from water, which can lead to pattern collapse and reduced efficiency in the sublimation drying process, particularly due to the need for ultra-low-temperature nitrogen gas and high running costs.
Innovation Solution
A method involving the placement of a liquid sublimation agent on the substrate's front surface and supplying a high vapor-pressure liquid without water to the rear surface, followed by vaporization and cooling to solidify the sublimation agent, while preventing water contamination and using a high vapor-pressure liquid at a temperature higher than the sublimation agent's freezing point to reduce costs and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultra-low-temperature nitrogen gas is continuously supplied to form a frozen film for sublimation drying, then pattern collapse is prevented, but equipment complexity and running costs increase enormously
Solution Approach 1:
The patent replaces expensive, continuous ultra-low-temperature nitrogen gas supply with a simple liquid sublimation agent that is applied once and then sublimates naturally. The sublimation agent film is a temporary, disposable layer that performs the drying function without requiring complex continuous supply equipment.
Solution Approach 2:
The patent changes the physical state and temperature parameters from ultra-low-temperature gas (−60°C nitrogen) to ambient-temperature liquid sublimation agent. This parameter change eliminates the need for complex cooling and gas supply equipment while maintaining the sublimation drying effect.
2Stability of the object's composition
If cold water is supplied to the rear surface to solidify the sublimation agent, then a sublimation-agent film is formed, but water may mix with the film and obstruct sublimation or cause pattern collapse
Solution Approach 1:
The patent introduces a temperature-controlling fluid as an intermediary between the cold water and the sublimation agent film. This fluid acts as a buffer that transfers cooling effect without allowing direct water contact with the sublimation agent film, thus preventing contamination while maintaining film formation.
Solution Approach 2:
The patent segments the cooling process into two separate sides: cold water is supplied to the rear surface while the front surface maintains the sublimation agent film. This spatial segmentation prevents water from contacting the film while still achieving the necessary cooling for film solidification.
3Productivity
If a liquid sublimation agent is supplied to the front surface and cooled by cold water to the rear surface, then sublimation drying is achieved, but the process requires precise temperature control to prevent water mixing
Solution Approach 1:
The patent enables the sublimation agent to perform self-cooling through its own sublimation process. As the sublimation agent transitions from liquid to gas, it absorbs heat and cools itself, eliminating the need for external temperature control units and complex cooling systems.
Solution Approach 2:
The patent utilizes the phase transition of the sublimation agent from liquid to gas as the primary cooling mechanism. This self-cooling effect during sublimation replaces the need for active temperature control systems, simplifying the equipment while maintaining drying efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively forms a solid sublimation-agent film, prevents water contamination, and reduces costs by eliminating the need for temperature control units, while ensuring efficient sublimation drying and minimizing pattern collapse risks.
Implementation Method 1
losing vaporization heat in response to vaporization of the high vapor-pressure liquid, and thereby cooling the sublimation agent
Implementation Method 2
solidifying the sublimation agent, and thereby forming a sublimation-agent film
Implementation Method 3
a sublimating step of sublimating the sublimation-agent film
Data Source
AI summary
A substrate drying method includes a sublimation-agent-liquid-film placing step of placing a liquid film of a liquid sublimation agent on the front surface of the substrate, a high vapor-pressure liquid supply step of supplying a high vapor-pressure liquid that has vapor pressure higher than the sublimation agent and that does not include water to a rear surface that is a surface on a side opposite to the front surface in the substrate, a vaporizing/cooling step of, after the liquid film of the sublimation agent is placed on the front surface of the substrate, stopping supplying the high vapor-pressure liquid, and, as a result, losing vaporization heat in response to vaporization of the high vapor-pressure liquid, and, as a result, cooling the sublimation agent, and, as a result, solidifying the liquid film of the sublimation agent and a sublimating step of sublimating a sublimation-agent film.